Effect of impurities with retarded interaction with quasiparticles upon critical temperature of s-wave superconductor

TL;DR

This paper proposes a generalized theory for disordered metals with impurities causing retarded quasiparticle interactions, showing that such impurities can significantly increase the critical temperature of s-wave superconductors, potentially up to room temperature.

Contribution

It introduces a new theoretical model where retarded impurity interactions violate Anderson's theorem, demonstrating impurity-induced enhancement of superconducting critical temperature.

Findings

Impurities with retarded interactions can increase the critical temperature.

Critical temperature can surpass that of pure superconductors under certain conditions.

Impurities may enable superconductivity at room temperature.

Abstract

Generalization of a disordered metal's theory has been proposed when scattering of quasiparticles by impurities is caused with a retarded interaction. It was shown that in this case Anderson's theorem was violated in the sense that embedding of the impurities in s-wave superconductor increases its critical temperature. The increasing depends on parameters of the metal, impurities and their concentration. At a specific relation between the parameters the critical temperature of the dirty superconductor can essentially exceed critical temperature of pure one up to room temperature. Thus the impurities catalyze superconductivity in an originally low-temperature superconductor.